Question

A 22 year old female with no previously known medical history presented to her primary care doctor for a 2 month history of intermittently increased spasticity of her upper extremities and intermittent paralysis of her lower extremities with no known cause.

She states that her symptoms seem to “come and go” without a known cause, usually worse in the mornings. Her biomedical engineering college professors have not been very accommodating to her symptoms, however, and have instructed her to be seen by her primary doctor to “rule out mental issues.” While discussing her symptoms, she also mentions that she noticed worsening blurriness with ophthalmalgia (pain) while moving her eye which is constant. She endorses a mild history of depression which began when she was 16 but which was never treated, around the same time that she was diagnosed with infectious mononucleosis.

Her family doctor, concerned about the intermittent nature of the symptoms, instructed her to attempt to stretch in the mornings before heading to class and to return in 2 weeks if her symptoms did not remit. Approximately 1 week after her primary visit, she began to experience severe, knife-like shooting pains in her bilateral upper and lower extremities, in addition to a severe headache. Her roommate, concerned, called an ambulance and the patient was immediately taken to the University Hospital. While at the University Hospital, she underwent an emergent MRI of the brain with contrast, which revealed significant demyelination (death of neurons) in the periventricular zones (in proximity to the lateral ventricles of the brain). Neurology was immediately consulted, and, after viewing her imaging and labs, was convinced that a chronic inflammatory process was occurring in this patient. The patient, prior to being discharged from the hospital after other disorders had been ruled out, was prescribed Gabapentin and asked to follow up with a neurologist as an outpatient.

Further outpatient imaging 3 months later revealed worsening demyelination in the brain and the initial stages of demyelination in the cervical and thoracic spinal cord sections; lumbar puncture testing was also performed, which was revealing of increased numbers of macrophages, CD8 T cells, and anti-myelin IgG antibodies, revealing of a diagnosis of Multiple Sclerosis.

Please answer the following questions:

• Given the diagnosis of multiple sclerosis, what type of hypersensitivity reaction is most likely occurring in this young female?
• Given your answer in number one, what type of immune cells are most likely active in this patient?
• What type of interferons are most likely involved in the activation of the immune system components involved in this disease?

Answer 1

i. In this case we see that the girl has increased numbers of macrophages, CD8 T cells, and anti-myelin IgG antibodies. Since, her body is not performing an antibody-mediated response but rather going through a cell-mediated response, hence it can be said that Type IV hypersensitivity is most likely occurring in this young female which is causing inflammation and destruction of Myelin as a target antigen.

ii. There are two major types of immune cells in our body- T cells and B cells. In multiple sclerosis, the T cells activates in the lymph and flows through the blood vessels and enters the central nervous system. Back in there T cells liberates certain chemicals to cause inflammation and destruction to myelin, nerve fibers and the cells that make myelin. So it can be said that T-cells are most likely active in this patient

iii. Type II interferon, immune or gamma interferon is mainly secreted by T cells, and hence are most likely involved in the activation of the immune system components involved in this disease